Terroa

Terroa is a proposed taxonomic category offered by biologist Peter Ward in his 2005 book "Life as We Do Not Know It". Ward defines "Terroa" as containing all life on Earth which uses double-helix DNA to store hereditary information and which creates proteins using the twenty left-handed amino acids -- in other words, the three domains, Archaea, Bacteria, and Eukarya.

Ward indicates in his book that he offers the new category in order to distinguish the Earth life presently known to science, from both extraterrestrial life and from forms of life on Earth itself which use other methods of hereditary (Ward places viruses in this other category).